As summer outings go, it doesn't get much more wholesome than blueberry picking.

Fresh country air and exercise, teaching the kids where their food comes from, a bucket full of tasty spray-free antioxidants to take home and make into jam - as long as you're happy to overlook the fact we drove 320km return to find a pick-your-own orchard that was open on the right day.

Sigh. All that green goodness undermined by about 60kg of carbon emissions (according to the calculator here). How many blueberry bushes would we have to plant to make up for that?

Perhaps it's because I grew up in the Bay of Plenty that I had always assumed pick-your-own orchards were everywhere, if only you could be bothered looking for them. And I hadn't bothered to look for them until I got the idea this summer of taking the kids out berry picking and then making the bounty into preserves.

It was then that I discovered how rare pick-your-own orchards have become, particularly if you want to go in early summer, as I did. After a fruitless internet search and phone-around, I concluded that with the limited options in and around Auckland we would have to go further afield (all puns intended).

It turned out that the Waikato was better served with pick-your-own offerings, so we ended up combining the fruit-picking adventure with a planned visit to Grandma's house in Hamilton.

So, on a stifling Monday morning we plunged buckets-in-hand and gumboots afoot into the fertile peat fields of Blueberry Country near Ohaupo, 25 km south of the Hamilton CBD.

With 120 hectares, the family-owned property claims the title of the largest blueberry orchard in the country. As well as a thriving commercial operation supplying fresh and frozen berries to supermarkets in New Zealand and overseas, Blueberry Country has a lucrative sideline in manufacturing blueberry processing equipment. And from early December to mid-March it opens up some of its most heavily fruiting fields to pick-your-owners.

General manager Warrick Macdonald says allowing people to come in and see where their berries come from is good PR for the blueberry industry. "Our philosophy is about trying to get people enthusiastic about blueberries."

He doesn't buy the theory that I heard several times on my search that allowing people to pick their own fruit creates a health-and-safety nightmare, or it's an administration hassle. And he certainly doesn't believe that people aren't interested anymore. He says Blueberry Country gets more public pickers every year and it's not unusual for people to drive from Auckland to Ohaupo just to go on a berry-picking mission. This prompted the company to also open up its smaller Ngatea orchard (95 km south-east of Auckland's CBD) to pick-your-own enthusiasts.

To be honest, I'm not sure how enthusiastic the kids will be. We've always had fruit and veg growing in the backyard so it's not a novelty for them to discover where it comes from. But with our one attempt at growing blueberries ending in dried-up failure, they're more accustomed to finding the little berries in a plastic punnet in the fridge rather than in the garden. That's if the blueberries even make it into the fridge - we have been known to get to the checkout at the fruit shop with two empty punnets.

Still, in hindsight I erred by being too busy chatting to Warrick when we first arrived at the rows of berry bushes to explain to my boys that the little blue balls were actually edible.

The 2-year-old's interest in picking wanes before it waxes, when he discovers that the bucket he's been issued with makes a good hat, that recent downpours have created splashable puddles in the peat, and that Grandma has packed snacks.

On the other hand, the 4-year-old immediately gets to work, empowered by stompy gumboots, his very own bucket, and the responsibility of an important job. He happily wanders far down the rows, which stretch out to the horizon, lost in the quiet challenge of his search for perfectly ripe dusky blue-grey fruit. After we stop for lunch by the side of the road he begs to go back and pick some more.

I don't realise quite how conscientious he's being until he announces he's finished - with a healthy load in his bucket - and asks very politely if he is allowed to eat one of his berries. This prompts a eureka moment in the 2-year-old, who peers at the blueberries on the bush as if he's noticing them for the first time. "Leo eat one?" he says. And then he forgets about puddles and bucket-hats and crackers and gets absorbed in the hunt - just as it's time to leave.

When we return to the orchard shop to weigh and pay for our fruit ($15 for 1.6 kg, thanks mostly to Grandma's efforts), the 2 year old has nothing in his bucket and a suspiciously blue mouth. Though a sign at the door of the shop says the staff reserve the right to search your car for hidden plunder, Warrick says they operate under the theory that kids will return with empty buckets and full bellies.

We indulge in refreshing blueberry icecreams before setting out for the long, hot drive home. Perhaps I should have bought a few of the blueberry plants for sale at the shop, to offset those carbon miles.

Take your pick: a selection of pick-your-own orchards

AUCKLAND REGION

*Best Berries: A northwest-Auckland collective of strawberry growersPYO strawberries: Open for PYO at end of season. See website for updates.